Registering new SQLValidator implementations

[lucean]

I am attempting to register a SQLValidator implementation (with some custom rules) in my Superset v5.0.0 deployment, but I've come up against an issue with the implementation of ValidateSQLCommand (or perhaps a limit of my understanding of this feature).

I've updated the configuration for the SQL_VALIDATORS_BY_ENGINE dict in my superset_config.py file to include a reference for my engine:

SQL_VALIDATORS_BY_ENGINE = {
    "presto": "PrestoDBSQLValidator",
    "postgresql": "PostgreSQLValidator",
    "mysql": "MySQLValidator",
}

However, the code which resolves this SQL Validator name is in superset/sql_validators/init.py, with a hardcoded reference to the implementations provided by Superset (for Presto and PostgreSQL):

def get_validator_by_name(name: str) -> Optional[type[base.BaseSQLValidator]]:
    return {
        "PrestoDBSQLValidator": presto_db.PrestoDBSQLValidator,
        "PostgreSQLValidator": postgres.PostgreSQLValidator,
    }.get(name)

The function defined in this file (get_validator_by_name) is then used by the ValidateSQLCommand to run the validation implementation. I have an implementation for MySQLValidator (extending BaseSQLValidator)

Have I misunderstood the intended mechanism for bringing your own SQLValidator implementations? It seems that there's no way to do this at the moment without modifying the behaviour of the get_validator_by_name function. Ideally, I'd be able to affect this through modifying the configuration only - maybe something like:

superset/sql_validators/init.py

def get_validator_by_name(name: str) -> Optional[type[base.BaseSQLValidator]]:
    provided_implementations = {
        "PrestoDBSQLValidator": presto_db.PrestoDBSQLValidator,
        "PostgreSQLValidator": postgres.PostgreSQLValidator,
    }

    return { **provided_implementations, **SQL_VALIDATORS_BY_NAME }.get(name)

and

superset/config.py

# A mapping from the named SQLValidator implementations and the
# classes which provide the validation. Implementations are provided
# for the PrestoDBSQLValidator and PostgreSQLValidator in the
# sql_validators module
SQL_VALIDATORS_BY_NAME = {
  "MySQLValidator": superset.custom.MySQLValidator,
}